aa former industry term for a quality of silver plate equivalent to 3 Troy ounces of silver per gross of teaspoons; also known as medium.


abalone pearl – (a-bal-o’ nee) Pearl from an abalone, usually showing the iridescent colors characteristic of the interior of its shell.


abrasive – Any material used for grinding, emery, oilstone powder, carborundum, levigated aluminous oxide, etc.; or for polishing (which is just a finer grade of grinding), fine abrasives like diamond powder, diamantine, sapphire, rouge, etc.


abrasive points – Grinding points of various shapes, mounted on 3/32” shanks and used in flexible shaft machine for metal removal.


abrasive wheels – Emery and diamond encrusted wheels in various binders, used on mandrels in flexible shaft machine for metal removal and finishing.


absorption band – Dark lines interrupting the spectrum as viewed through a spectroscope. The specific locations of these interruptions are characteristic of some gemstones and thus can be used in gemstones identification.


A.C. – Abbreviation for alternating current; electricity which reverses direction at a stated rate (cycles) per second- for example “60 cycles A.C.”. It must be employed for demagnetizers, and for electric clocks that are driven by public service current. See also D.C.


acceleration – A gaining rate superimposed on the regular rate of a time-piece, particularly of new marine chronometers during their first year’s service. This peculiarity is explained to variously by authorities to be considered well understood. It disappears naturally as the balance and its spring continue in use.


Accuform – Trade name for refractory material for holding parts in position during soldering.


accumulator – A condenser for storing electrical energy, used in electrical clocks and watches.


Accutron – (Ac’ cu’ tron’) Brand name for the sonic timepiece introduced by Bulova Watch Co. in October 1960. A turning fork replaced the traditional balance wheel and hairspring, its vibrations being converted mechanically to rotary motions and transmitted through a gear-train to the hands.


acetin acid – A form of vinegar used for purposeful erosion of steel parts such as broken screws from watch parts. Also, an adhesive for some plastics.


acetone – A liquid used as an ingredient in solutions for cleaning watches, and as a solvent for resins and fats. It is well to avoid using acetone near an open flame, as its vapor is highly flammable.


acetylene – A colorless gas, C2 H2, highly flammable. Used with air or oxygen in a torch for soldering, welding and melting metals.


achroite – (a’kro-ite) A varietal name, like rube-lite, indicolite, etc., for colorless tourmaline.


achromatic – Without color, such as “achromatic sapphire” for white sapphire.


acid bottle – A specially designed container for dangerous acid used in jewelry work, and for blue-remover acid for watch work. The body of bottle is at least as wide as high, to prevent upsetting; the stopper fits with a ground glass joint, and has a glass stem, reaching almost to bottom of bottle, for applying acid.


acid gold – A process whereby a design is acid etched into the body dinnerware, then painted with liquid gold which is fired on and burnished.


acid test – 1. Fir determining the karat-quality of gold. This includes a black porous stone slab, a set of test needles with assorted karats of gold on the tips; and a bottle of nitric acid. Gold to be tested is rubbed on the stone; beside its “track” is rubbed another with one of the test needles of known karat. Acid is applied over the two tracks. If the needle track stands and the other one disappears under the acid, a lower karat needle is tried next, and so on, until the acid ha same effect on both tracks; the final needle karat is then known to be the karat of the gold tested. See KARAT. 2. Diamonds. Boiling diamonds in concentrated sulphuric acid to remove color coating.


acier – French for “steel,” stamped inside Swiss made watch cases of stainless steel.


actual-lock – See DROP-LOCK.


adamantine spar – (a-da-man’ teen) An early European name for corundum, especially a dark grayish brown variety from India.


adamas – Greek word originally meaning “incombustible.” with reference to iron, iron alloy, gold, sapphire and carbunculus; probably first applied to diamond by the romans in the 3rd Century B.C. The Romans used diamonds from India as cutting tool; valued them above all other substance not only for their rarity and supreme hardness but also for their magical powers as an “invincible forxe.”


adamite – A zinc arsenate found in some abumdance in Mapimi, Duranga, Mexico. The yellow-green crystal clusters have been used in some bits of hand-crafted jemerly which exploit the natural crystal shapes.


addendum – The acting portion of a gearwheel tooth or pinionleaf that extends outside the true diameter or pitch circle.


Adelaide ruby – A local misnomer, like most locality modifications preceding the name of the gem, in this case for a red Australian garnet.


adhesive – A substance that causes materials to adhere to each other as, cement, glue, epoxy, shellac, ect.


adinol – A German name for a silicified diabase or porphyry, and best regarded as an impure gray-brown jasper.


adjusting rod – A long rod with sliding, adjustable weight used to obtain maximum, uniform mainspring.


adjustment – Result of work done on watches to improve accuracy of timekeeping after manufacturing, by altering the forms and relations of parts, differentiated from REGULATING. The usual adjustment are to temperature, positions and isochronism. See REGULATING.


adularescence – A bluish or white sheen resulting from the internal reflections from twin lamellae. The same as “schiller” or labradorescence, but this refers specifically to the light-colored feldspar or moonstone. See ADULARIA; LABRADORITE; FELDSPAR; MOONSTONE.


adularia – (ad-you-lare’ ee-a). A pure, colorless to milky potash aluminum silicate feldspar which occurs at its best in the Alps. However, most moonstones, the variety with the schiller color, are found in Ceylon. See APHROSELINE, CEYLON OPAL, WATER OPAL, ICE SPAR, FISH EYE, WOLF’S EYE, GIRASOL, SILVER STONE.


aëroides – A local American misnomer for pale, sky blue aquamarine.


affix – An attachment to a balance to compensate for errors in temperatures not corrected by the balance itself.


African emerald – 1. Misleading name for green fluorite. 2. Greenish yellow emeralds from Transvaal. The rich green emeralds, found in 1957 in Rhodesia near Sandawana, are called by the letter name.


African jade – A compact green and white massive grossularite garnet from the Transvaal. Also know as South African jade and Transvaal jade.


African tourmaline – A trade term for a light, blue-green brilliant tourmaline, of any origin.


agalmatolite – A soft, compact, yellowish or reddish brown amorphous mineral, an alteration product of other rocks which is widely used by the Chinese for cheap carved objects. Also called pagodite. The word is from a Greek word meaning “an image.”


agaphite – A turquoise varietal name, given is 1806 to a conchoidal turquoise occurring in a porphyry or lava. Named for Demetrios Agaphi, who examined the Persian deposits


agate – A multi-colored microscopically crystalline, variegated chalcedony. It may be banded, irregularly clouded or have visible impurities as in moss agate. A very common variety of quartz coming at present principally from Brazil. Locally abundant in the West. It is one of the many varieties of quartz. Most commercial German agate is artificially. (See ALEPPO STONE, CARNELIAN, EYE AGATE, IRIS AGATE, MOSS AGATE, SARD, etc.). Used in horology for knife-edge suspensions for clock pendulums, and for the jaws of fine poising tools for watch work.


agate jasper – A many-colored intermediate between chalcedony and agate. It formerly was called “jaspe fleuri” by jewelers and came principally from Sicily.


agatized wood – Wood petrified through cell by cell replacement by jasper; that from Arizona is often brightly colored and attractive. Petrified Forest National Monument in Arizona is a preserve where the logs may be seen in place.


aiguilles – French for “hands,” inscribed on some Swiss watch case caps to show where to apply key to set the hands.


air-friction – An effect on the motion of parts of timepieces, particularly balances and pendulums, caused by their passage through air, which tends to impede their movements.


air-gap – The distance between a wheel or balance and the closest object is a coil or magnet.


a jour – The name for an open setting, so that the underside of the stone may be seen. Originally restricted to French, but now a widely used term.


akori – A porous coral used in ancient times in jewelry, especially West Africa and Samoa. Name later applied to substitutes such as pearls, coral, rock and glass.


alabandine ruby – Misnomer for almandine garnet, both of which names derive from Pliny’s name for a source in Asia Minor, Alabanda. The name has also been applied to spinel.


alabaster – A massive, fine-grained variety of gypsum, hydrated calcium sulfate, usually white, yellowish or pink. It is often used for carving and older clock cases as it is very soft and easily tinted. It is found at many localities.


alalite – Local misnomer for diopside arising from the name Val d’ Ala. This locality in northern Italy is known for its garnets as well, but few gems are found there.


Alaska black diamond – Misnomer for hematite.


Alaska diamond – Misnomer for quartz.

albite – The white sodium feldspar common in rocks and sometimes found in crystals which show a bluish schiller, like moonstone. Albite moonstone is another name sometimes applied to stones of this type.


alcohol – Liquid used for cleaning watches and jewelry, and as a solvent for removing cements and for making liquid cements. Grain alcohol is more costly and better, where small quantity is needed. Wood alcohol or denatured grain alcohol is much cheaper, being tax free, and is used where greater quantity is required.


alencon diamond – Misnomer for quartz.


Aleppo stone – An eye agate, believed in parts of the East to be of value in treating a kind of sore known as an Aleppo boil. See CYCLOPS AGATE.


Alessandrine turquoise – Trade name for the best quality of turquoise coming from the world’s oldest known deposits, on the west coast of the Sinai Peninsula. Also called Egyptian turquoise.


alexandrite – A variety of chrysoberyl which because of its unusual absorption changes color in different lights. It is green in daylight and wine-red in most artificial lights. It was found originally in the Urals and since in Ceylon, Brazil and Tanzania, and was named in honor of Alexander II of Russia. Color changes vary in different stones and most good “night-stones” and apt to be very dark in daytime. Now made synthetically, like emeralds, for costly substitutes. The so-called synthetic alexandrites of the past, widely sold for years al low prices, are actually synthetic sapphires (rarely spinels) colored by vanadium and not true synthetics in the accepted sense. They should have been called simulated alexandrites, or alexandrite synthetic corundum.


alexandrite cat’s-eyes – A chrysoberyl with parallel inclusions, cut cabochon so that it shows a light streak, which changes color in different lights. SEE CAT’S, ASTERISM, ALEXANDRITE.


all chromatic – Refers to the coloring by minor impurities of stones, which, if pure would be colorless. Few stones are Indio chromatic, that is, colored by essential ingredients.


alligator watch band – A watch strap made of alligator, crocodile or such simulated material.


alloy – 1. A metal to be melted with another to form a compound metal with qualities suitable for some particular use. 2. the compound metal resulting from melting two or more metals together, whose properties and melting point may differ from those of its components. Derivation. Through the erroneous fancy that Fr. aloi was = a loi ‘to law,’ the word, meaning originally simple combination, union,’ come to be used specially of the mixing of baser metal with gold or silver in coinage, so as to bring it to the recognized standard, and hence of the standard itself. – Oxford English Dictionary.


alluvial – Deposits by wind or water, in which heavy minerals are often concentrated. Diamonds and gold are frequently mined from the type of deposit. See PLACER.


almandine – (al’man-deen) A purplish-red, iron aluminum garnet. Once called almandine or almandite, the name is derived from a source known as Alabanda in Asia Minor. Almandite has been dropped in accordance with current usage, the ine is now preferred by mineralogists. Common obfuscating names include Ceylon Ruby, Cape garnet, vermeille garnet. Syrian garnet, and, from ancient texts, carbunculus alabandicus. See ALABANDINE RUBY.


almaschite – A remarkably fluorescent amber from Olanesti in Rumania. See DELATINITE.


Alpine diamond – Misnomer for pyrite.


alum – Aluminum ammonium sulphate, used in powered or lump form, dissolved in water, for rusting out broken screws imbedded in watch plates so as not to be mechanically removable. Keeping the solution hot speeds up the rusting process. Alum was also used for reducing perspiration of the hands of workmen, by rubbing them with a lump of alum; or by washing the hands in alum solution.


Alumag – Trade name for spinel, as an imitation diamond, from the composition, a magnesium aluminate.


aluminum oxide – An effective, hard abrasive made in various grades and grain size.


amalgam – An alloy of mercury with another metal or metals. Amalgams of gold are used in some processes of gold plating. An example of gold amalgamation in the common one where in a piece of gold jewelry becomes accidentally saturated with mercury, which makes the gold white and brittle. The mercury may be driven out of the gold by repeating heating of the piece.


amaryl – Name given by H. Michel to a light green synthetic corundum.


amatrix – Or amatrice, the name coined for the mixture of green variscite with chalcedony and quartz, cut cabochon, and mined at Stockton, Tooele County, Utah. “American matrix” is the origin of the name.


amazonite – Or Amazon stone, a green variety of potash feldspar known as microcline and frequently found in pegmatite dikes and usually white or pink. Found in Virginia, Russia, Colorado, Brazil and Madagascar in abundance, locally elsewhere. An old name, referring to the Brazilian deposits. See BARAKETH.


amber – A fossil resin. Mineralogists have separated many resinous compounds which may be grouped under this name. It is the preserved gum of coniferous trees and mostly comes from and near the shores if the Baltic in East Prussia. Burma, Romania, Sicily, New Jersey and Canada have produced similar resins. Often insects which were entrapped as the gum exuded have been preserved and their shells are to be seen in finished pieces of amber. See ALMASCHITE, BURMITE, BALTIC AMBER, BECKERITE, BASTARD AMBER, BONY AMBER, CLOUDY AMBER, COPAL, DELATINITE, FOSSIL RESIN, FROTHY AMBER, SEMI-BASTARD AMBER, SUCCINITE.


ambroid – Name applied to amber chips and flakes which have been pressed under heat to build up a solid mass. Also called pressed amber.


American cut brilliant – A diamond proportioned in accordance with the calculations published in 1919 by mathematician Marcel Tolkowsky, “ the only aim being to obtain the liveliest fire and the greatest brilliancy.” The figures, girdle diameter considered as 100%: table diameter, 53%; crown thickness, 16.2%; pavilion thickness; 43.1%; table-to-culet depth, 59.3% plus girdle thickness; angle of crown facets, 34.5°; angle of pavilion facets, 40.75°. Also called Ideal Cut. American Gem Society grades of cutting (1975) are defined in terms of degree of departure from such proportions and finish. See BRILLIANT; CUTTING GRADE; EUROPEAN CUT; TOLKOWSKY, M.; MORSE, HENRY.


American Gem Society – A selective, non-profit professional organization of jewelers of the United States and Canada, seeking to advance gemological knowledge, guide ethical practices, and enhance the public image of the industry; founded in 1934 by Robert M. Shipley. See REGISTERED JEWELER; CERTIFIED GEMOLOGIST.


American jade – Misnomer for a compact grass-green variety of vesuvianite, a calcium aluminum silicate, occurring in California and also known as californite.


American lathe – A term used in other countries to describe a live-spindle, spit-chuck lathe with flat, horizontal bed.


American ruby – Misnomer for a garnet. Prefixes of this sort preceding name of a more precious stone, such as emerald, ruby or diamond, almost without exception indicate an attempt to create a demand for a less valuable stone by deceiving the purchaser into thinking that the relationship to the true gem is more than superficial. It cannot be too strongly decried.


American Watchmakers Institute – National association of watchmakers organized in June 1960 in Chicago, a merger of the Horological Institute of America and the United Horological Association of America.


amethyst – A purple variety of coarsely crystallized quartz. The origin of the color is unknown. It is a popular gem and comes in many shades, the deepest, often called Russian or Uralian amethyst, being the most desirable. Almost all amethyst comes from Brazil and Uruguay today. See AHLAMAH, BAHIA AMETHYST, BISHOP’S STONE, URUGUAYAN AMETHYST.


ammeter – An instrument to measure the amperage of a current in a watch or clock.


ammolite – Doublet made of lumachelle. See LUMACHELLE.


ammonia – A liquid used as an ingredient of various solutions for cleaning watches and jewelry. The variety of ammonia usually meant is formulas for cleaning solutions is “household ammonia,” a weaker solution of ammonia gas in water than other commercial ammonias


ammonia maser – Microwave amplification of simulated radiation.


ammonium sulphide – A compound used to oxidize copper, silver and low karat gold.


amorphous – “Without form,” and means that there is no regular internal arrangement of the molecules, as opposed to crystalline, in which there is such an arrangement, though fracture or cutting may have removed any external indication of that structure.


ampere – The unit of measurement of electrical current passing though a circuit whose resistance is one ohm.


amphibole – (am’fib-bole) A group of minerals whose compositions are related, all being complex silicates, and most of which have only mineralogical interest. White, green, yellow, or brown nephrite, one of the minerals included in jade, is the most important of this group from a gem standpoint. Blue crocidolite is an asbestos-like member of the group which is important because it has been replaced by quartz in asbestos mining areas in South Africa and Australia, and the preserved fibrous structure shows in the “tiger-eyes” cut from this material. See NEPHRITE, HORNBLENDE, TREMOLITE, PYROXENE.


amplitude – Measure from the point of the rest, the outermost swing of a balance, pendulum or oscillating body.


amplitude graphometer – An electronic instrument which indicates the amplitude of a timepiece on a metered scale. Synonym: amplitudoscope.


amulet – A charm worn by the superstitious to ward off ill, or accomplish some desired end.


amygdule – An almond-shaped or rounded nodule from an amygdaloidal basalt. Such as volcanic rock has the small original trapped gas bubble cavities filled with mineral deposits, such as agate, subsequent to the solidification of the lava, possibly during weathering of the upper levels, by precipitation from downward percolating saturated solutions.


analog – A timepiece with dial, hands and numbers or markers, its total display being analogous, or comparable, to a 12-hour time span.


anatase – (an’na-tase). An unusulas form of titanium oxide, very rarely used as a gem. It strongly refracts light, is brown to blue in color, and has been found in cut-able stones only in the Alps. It is questionable if stones of this have ever been cut except for collectors.


anchor escapement – A term describing the escapement used in most clocks, the pallets resembling the flukes of an anchor.


Ancona ruby – Misnomer for quartz


ancre – The French (Swiss) term for the lever of a watch or clock.


ancre escapement – “echappement a’ancre”. See LEVER ESCAPEMENT.


andalusite – (an-da-loos’ite). An interesting aluminum silicate which is sometimes cut as a gem. It crystallizes in the orthorhombic system, which means that it is referred to three different axes at right angles to each other. When viewed in these different directions it has a pronounced pleochroism, from greenish to yellow to reddish brown. This color difference shows best in stones which are emerald-, oval or cushion cut. It is found in rolled pebbles in Brazil and Ceylon. A variety known as chiastolite contains many black impurities which are pushed aside into definite positions by the growing crystal, resulting in a pattern of a white cross or regularly spaced white areas in a black background. It is found in many places, Massachusetts, California, and Australia among others, and is used as a gem locally. The name andulusite is sometimes erroneously applied to brown tourmaline. See STEALITE, HOLESPAR, CROSS STONE, LAPIS CRUCIFER.


andradite – (an’dra-dite) A calcium-iron garnet; red, yellow, brown, green or black. Topazolite is pale green or brown; demantoid a brilliant green and the most valuable of the garnet group. See BOBBOWKA GARNET, TRANSVAAL JADE, SUCCIN-GARNET, VIRIDINE.


aneroid – A thin air-evacuated metallic box, used as a barometer or altimeter to test barometric pressure; in horology, to test barometric effects on timekeeping. Also used is some “perpetual winding” clocks.


angle – A geometric figure formed by two intersecting straight lines; the extent of arc of an oscillating body such as balance, pendulum, vibrating reed, etc.


anisotropic – (an’ice-o-trop-ik) Not isotropic, meaning that light does not pass through in different directions at the same speed. Anisotropic substance have the property of breaking light up into rays vibrating in different planes and traveling at different speeds. Crystalline substances not belonging to the cubic system have this property. See DOUBLE REFRACTION, SINGLE REFRATION, ISOTROPIC, LIQUID CRYSTAL DISPLAY.


anklet – An ornament of gold or silver or other metal, worn around the ankle in the same manner as the bracelet adorns the arm.


annealing – Process of heating metal which has become compact and brittle. The heating removes the brittleness and renders the metal soft and malleable, so it can be worked. 2. In glassware manufacture, the reheating and gadual cooling of glassware to reduce the stresses and strains which are the chief cause of breakage.


annular balance – The balance of a timepiece whose shape is that of an uncut ring.


anode – A term used in electroplating to denote the positive pole in a plating bath, to which is attached a bar of metal which is partly electro-deposited on the article to be plated. The latter is attached to the negative pole, or cathode.


anomalous double refection – (ah-nom’ ah-lus) Double refraction in a substance that is usually singly reflection, such as diamond, garnet, glass, or synthetic spinel, occasioned by internal strain. During polariscope examination, the extinctions tend to be irregular.


Antilles pearl – Not a real pearl, but a mother of pearl sphere cut from the iridescent shell of the Turbo snail, at whose apex there is a thick place which will permit the cutting of such a sphere. Also known as an oil pearl.


antimagnetic watch – A watch composed of metals not affected by magnetic influence. Rule 4 of the Federal Trade Commission’s Guides for the Watch Industry, amended 1970, says a watch may be called “antimagnetic” if its daily rate is not change more than 15 seconds by exposure in an electrical field of 60 Gauss for five seconds in a horizontal position.


anti-oxidizer – Any preparation used for preventing formation of an oxide scale on work undergoing soldering or other heat-treatment. For soldering jewelry, many trade-marked anti-oxidizers may be bought; or a preparation of half-and-half boracic acid crystal dissolved in grain alcohol may be painted over the work, and allowed to dry, before soldering. In heating steel for hardening, a coating of moistened soap applied before heating, is a good antioxidizer. See HEAT SHIELD.


antique reproduction – Jewelry. An obvious copy of the original but modernized to satisfy both contemporary taste and nostalgia for the old. b. a scrupulous copy, perhaps almost indistinguishable for the original.


antique shape – A gem shape; an elongated stone with sounded ends.


antiquing – A process whereby metal objects ate chemically treaked so that they take on color or patina associated with age. Silver and copper will gradually turn back upon immersion in a solution of liver of sulphur (potassium sulphide). Gold may be darkened by plating in a “Black Chrome” solution.


Antwerp rose – A manner of cutting diamonds popular in the 17th Century but now seldom if ever used. It is a rose cut with 12 to 24 facets, the upper facets being very flat. Also called the Brabant rose.


anvil – 1. A fixed, solid base which may be struck. 2. The fixed and of a measuring gauge. 3. In chronographs or repeaters, the part against which the hammers act.


Apache tears – Smoky-hued glassy prelatic obsidian nodules found in partially hydrated volcanic glass deposits. As cut stones, they resemble smoky quartz, but are singly refracting and much softer. Abundant near Superior, Ariz.


apatite – Calcium phosphate, the mineral which is number 5 in the Mohs hardness scale. Often transparent and highly colored, it makes an attractive, but little appreciated, gemstone for specialists. Hues include yellow, green, violet and colorless. Too soft for many uses, they are, are, nonetheless, occasionally used in jewelry; the yellow Mexican stones are the most abundant. Also known as ASPARAGUS STONE and MOTOXITE.


aperture – An opening or “window” in a dial or case to allow the display of a feature such as a date, day, moon phase, etc.


aphroseline – Greek name for adularia, meaning the splendor of the moon.


apparent time – The time indicated by a sun dial. Due to the eccentric orbit of the earth, high noon differs as much as 16 minutes from clock time. Clocks indicate an average, or “mean,” of solar time.


appliqué – Ornamental work or enrichment made separately and applied, fastened or mounted on another metal.


Appraisal – official valuation document made by a certified gemologist and expert in field of diamonds and metals.


apricotine – A local (Cape May, N.J.) name for reddish yellow quartz pebbles.


apyrite – Name given to peach-bloom colored tourmaline; a needless complication of the nomenclature.


aquagem – Trade name for a light blue synthetic spinel.


aquamarine – Sky-blue to greenish blue beryl. Aquamarine chrysolite is a misnomer for a greenish yellow beryl. Aquamarine emerald is a misnomer for doublets made of colorless beryl cemented by green glass. Aquamarine topaz is a misnomer for bluish topaz. Aquamarine triplet is the same as an aquamarine emerald.


aqua regia – A mixture of nitric acid and hydrochloric acid, used for testing high-karat gold by the stone-and-needle (touchstone) method; and for dissolving gold and platinum. An average proportion is three parts hydrochloric acid and one part nitric acid. Care must be taken in mixing these acids, to avoid damage my splashing; and not to breathe the chlorine gas that arises. Named aqua regia by medieval alchemists because it would attack the royal metals, platinum and gold. See ACID TEST.


arabesque – Decoration in the Arabian style; the features are geometrical outlines, flowers, fruits and foliage, combined and grouped; on clocks or watch-cases or dials, marquetry with scrollwork.


Arabian diamond – Misnomer for white sapphire.


aragonite – (a-rag’ on-ite) A form of calcium carbonate and an important constituent of the pearl. Also widespread as a non-gem material. Though less common than calcite, it is a differently crystallized variety of the same compound. See CALIFORNIA ONYX, MEXICAN ONYX.


arbor – A part of a mechanism that rotates; or that turns in pivot bearings while holding something that turns, as a pallet arbor, balance staff, pinion on a wheel, etc. A stem (winding) arbor and a barrel arbor are examples.


arc – Part of circumference of a circle; the path of motion of a pendulum or of the balance of a watch.


arch dial – Clock dial with upper part in form of a half-circle; the type helps fix age of old long-case or mantel clocks. Arch dials were introduced about the year 1700. Prior to then, dials of such clocks were square with a straight edge at top. The arch at first was decorated with ornamental engraving, marker’s name, etc.; later it accommodated mechanical features like moon’s phase disc, or equation work.


arcing – The detrimental action of an electrical surge across a gap between two contacts such as in an electrical clock watch.


Arizona diamond – Misnomer for quartz.


Arizona ruby – Like most such names, a misnomer for garnet.


Arizona spinel – Misnomer for garnet.


Arkansas diamond – An especially bad misnomer for quartz. In the case it is more than ordinarily to be condemned, since genuine diamonds are also found in Arkansas, and there could well be confusion.


Arkansas stone – A whitish gray stone used as a fine abrasive in solid or powdered form to prepare graves or pivot for polishing.


armature – That part of an electric-motive device in which force is induced as in a clock, watch or motor.


Armenian stone – Lapis lazuli.


Art Nouveau – Late 19th and early 20th Century style of art that found its way into jewelry. It is generally depicted as curved, flowing, assymetrical forms, recurring and intertwining as leaves, flowers and insects.


artificial stone – See IMITATION; SYNTHETIC.


asparagus stone – Yellow-green transparent apatite, originally from Murcia, Spain.


assay – The analysis of ores, bullion and alloys to determine the proportion of precious metal content. Tests accurate to within one-part per thousand, made by the British Assay Offices of articles made of karat gold, may be obtained from scrapings as one milligram (30/1,000 oz).


Assay Office – 1. Parts of the Treasury Department; the U.S. Assay Office in Denver tests ore samples; that is New York assays and reclaims gold and silver for government agencies and performs “umpire” assays of bullion for private owners 2. In certain foreign countries, governmental agencies place their mark on precious-metal fabrications.


Asscher – diamond shape named after the world-renowned cutter Joseph Asscher; square with cut corner.


assemble – Horology. To put parts of a watch or clock together to make up a complete timepiece.


asteria – Asteriated or asterism, all refer to a property possessed by some gem stones when cut cabochon or when viewed in transmitted light, if reflecting the light as a star, or surrounding the light source with radiating rays. Star sapphires are best known, but star garnet, beryls and rose quartz are known; in the latter it is very common. It is caused by an internal arrangement of microscopic needles of an included mineral or of tubular cavities parallel to the shape the mineral has in nature. When all run in one direction they create an “eye” as in cat’s eyes.


astralite glass – An artificial product, much like aventurine glass, with blue flecks in dark ground mass.


astronomical time – 1. Sidereal time. 2. Mean solar time shown on a dial with hours numbered from 1 to 24 instead of from 1 to 12, or noon to midnight and midnight to noon. See SIDEREAL.


Atlas ore – A misnomer for malachite. Atlas pearls, spar, or stone in a fibrous, colorless, red, blue, or green calcite, which, when polished, has a silky luster. It can be dyed to resemble a cat’s-eye. The name is also applied to the still softer gypsum of the same character, also known as satin pear.


Atmos clock – A “perpetually wound” clock with torsion, suspended balance wound by changes in temperature.


atmosphere – In horology the units of pound per square inch (14.7 ft. at sew level) used to denote the test units of water-resistance to which watches are subjected.


atomic clock – A highly precise electrical clock with resonant frequencies of atoms or molecules of a gas such as ammonia or cesium.


auriferous – Designates an ore or a metal containing gold.


Australian ruby – Misnomer for garnet.


automata – Watches and clocks with moving figures of people, animals, etc., an art highly developed during the 17th, 18th and early 19th Centuries. Examples of it are in nearly all watch and clock collections. Automata of largest size are on some ancient architectural clocks in Europe.


automatic center punch – Manually powered punch used for marking locations on metal for accurate drilling of holes.


automatic watch – See SELF-WINDING.


auxiliary compensation – An additional provision on the usual compensating balance, mostly on marine chronometers, to lessen the “middle” temperature error.


auxiliary power – Reserve power in a watch or clock to keep the balance or pendulum and hands moving during winding or in an electrical clock, the reserve power to maintain timekeeping until power is restored.


aventurine – (av-ven’tyour-een) A name with many applications. Used with quartz, it refers to a green variety of quartzite which contains flakes of green mica. Aventurine feldspars, such as sunstone, contain flakes of hematite which reflects light in certain positions. This is usually reddish brown in color. Aventurine glass is a very widely used product, now less so then formerly, which contains crystals of copper in a brown ground mass. The name originated through the accidental Italian (aventura-chance) discovery of this effect. This must be about the only instance when the jewelers have applied the name cheap artificial product to a better natural stone. Also known as goldstone and widely sold as a local product. See CHRYSOLITE, CHRYSOQUARTZ.


avoirdupois – A basis for weighting things other than jewels and precious metals. The unit is a pound containing 7000 Troy grains. The Troy pound contains 5760 grains. In buying old silver, when one’s Troy scales will not accommodate the large quantities involved, use avoirdupois weight; then convert this to Troy weight, allowing 14.583 Toy ounces per pound aoirdupois; and .9115 Troy ounce per ounce avoirdupois.


Awabi pearl – Japanese name for abalone.




axial thrust – End thrust or pressure on the ends of pivots of arbors.


axinite – (ax’in-ite) A complex mineral, a borosilicate of aluminum and calcium with iron and manganese, which is rarely cut as a gem. Usually it is clove-brown in color, though yellow and greenish shades are not unknown, Dauphiné in the French Alps supplied the most typical rough; some have been cut from Mexican material. It is rarely seen in the trade. The name refers to the wedge-shape of the natural crystals.


axis – A crystallographic axis is an imaginary line passing through the center of an ideal crystal, and parallel to the intersections of the principal faces. The crystal systems are based upon the axes, and range from three equal axes at right angles to each other in the isometric system, to three unequal axes at oblique angles to each other in the triclinic system. See CRYSTAL. The theoretical center of motion of an arbor or other rotating object.


ayr (water of) stone – Also called bluestone. A soft, compact-grained stone used in the form of a flat lap, or slip, with water, to flatten or smooth out imperfections in watch parts, etc., made of brass or other non-ferrous metals.


Aztec stone – A local misnomer for zinc carbonate, smitsonite.


azured – In blanks for wedding rings, or other jewelry made to be set with stones, the settings are said to be “azured” when each has the hollow for the pavilion of its stone formed in a square; the space below the girdle of the stone having form of a truncated pyramid.


azured quartz – A confusing name which has been applied to quartz pseudomorphs after crocidolite (tiger eye) in which the original blue color has been preserved. Also called sapphire quartz and siderite; no more desirable terms then the above.


azurite – A blue basic copper carbonate ore of copper, often associated with, and even altered to, the more stable green form known as malachite. Commonly cut into bright blue or blue-and-green cabochons. Soluble in acid and reatively soft, azurite must be handled with caution. See MALACHITE, CHESSYLITE.


azurlite – A now invalid name for chrysocolla-saturated chalcedony. See CHRYSOCOLLA.






back cock – The bridge of a timepiece supporting the rear balance or another pivots.


backlash – Play or freedom of motion; as when a wheel in a train is pushed backward.


backsurge current – In an electrical timepiece, current sent through a coil generates a magnetic field around it. When the current is stopped, the field collapses in the opposite direction.


Baffa diamon – Misnomer for quartz.


bagos de arroz – Literally “bags of rice.” A Brazilian term for long and flat rough diamonds.


Baguette – (bag-ett’) 1. A rectangularly-shaped small diamond or other gem stone. 2. A very small rectangular bracelet watch. (Originally, a French term describing a small watch worn as a ring).


Baguette setting – A rectangular-shaped stone with rows of step-like facets. If the baguette’s two long sides taper inward, it is called a Tapered baguette. Baguettes in long, thin cut rectangles are often used as enhancements to a lager center stone, or on a watch bezel.


Black Diamond – diamond saturated with graphite inclusions.


Bahia amethyst – (bah-ee’ah) Amethystine quartz from Bahia, Brazil. The locality is noted for the large size and purity of the material, but dark shades are rarer than in Southern Brazilian and Uralian stones.


Bahia emerald – A name now of no special significance, since there are several emerald sources in Bahia, Brazil, yielding stones with widely differing characteristics. Some, as in Salininha, are vanadium-pigmented. However, most, like those of Carnaiba and Conquista, are perfectly normal emeralds by any standards.


bail – A finding, connected to pendants or stones worn as pendants, etc. to accommodate a chain, cord or thong.


Bakelite – (bake’el-ite) A colorless plastic made from phenol and formaldehyde, and named for its inventor, Dr. L. Baekeland. It can be dyed any color and is often sold as an amber imitation. It can be readily identified by the formaldehyde smell which results when a hot needle is pressed into it.


balance – The part of a watch or chronometer whose vibrating, governed by its spring, perform the actual timekeeping that is indicated by hands on the dial. See BIMETALLIC, CUT, INTEGRAL, MONOMETALLIC, PLAIN, STAFF.


balance assembly – A group of parts in a timepiece comprising balance, staff, spring, and roller.


balance arc – The extent of the balance amplitude. See AMPLITUDE.


balance chuck – A lathe chick with boxlike opening to hold the balance and allowing only the pivot to extend through a tiny hole in the face for adjustment.


balance cock – The bridge housing the balance hole and cap jewels of a timepiece and secured at one end as compared to a true bridge, which is secured at both ends.


balance coil – An electromagnetic coil situated on a balance.


balance magnets – Permanent magnets mounted on a balance of an electrical timepiece.


balance screw – One of the screws threaded into the rim of a balance to supply an adjustable mass.


balance screw fixture – A scaffold upon which a balance rim is placed to allow changes or adjustment to its screws.


balance spring –The hairspring on a balance.


balance stop lever – The pivoted lever to stop the balance on a stop or hack watch.


balas – (bal’as) A term used in Brazil for a gem fragment of zonal tourmaline from which the outer layers have been removed to show the clear kernel. See BALLAS.


Balas ruby – A misnomer for red spinel. From rubin Balais from Balascia, a synonym for Badakshan, Afghanistan, which furnished the best stones in the Middle Ages.


Balbach process – Method of refining silver containing small amounts of gold. Anodes of impure silver are electrolyzed in an acidified silver nitrate bath; pure silver is deposited on a carbon cathode. Same as Thum or Tham-Babach process.


Bal de Feu – Trade name for man-made strontium titanate.


ball bearing – An arbor bearing containing a ring of steel or jewel balls.


ball clock – A clock whose apparent timekeeping or winding is governed by guided steel balls falling in tracks.


ball jasper – Masses of round, brown to red jasper ranging from nut to head sizes. Formerly found with iron concretions in Breqau. Probably an equivalent of the California poppy stone.


ball pearl – Name said to be applied to round American Freshwater pearls by the pearlers.


ballas – Rough diamonds in rounded shapes, unsuitable for cutting as gems, but very valuable for industrial uses. They have a confused, intergrown internal structure which makes cleaving through them impossible, and consequently, they are tougher them usual diamonds when used as tool tips.


Baltic amber – Amber from East Prussia and neighboring beaches. Most amber in commerce in mined in this locality.


baluster – A stem is said to be baluster-shaped when it has a swelled boss in the shaft. The term occurs with cups and candlesticks.


band – 1. A ridge or belt, usually plain but sometimes ribbed or decorated, about the main body of a vessel such as a coffee pot or a tankard.2. A wedding ring. 3. A watch strap or bracelet.


banded agate – Agate which has formed in a series of bands; most agate in trade is of this type. The bands are characterized by slight differences in pore spaces and grain size, usually the banding is exaggerated by differential dye absorption. Almost all banded agate in the trade is artificially colored. See AGATE, ONYX, SARD, etc.


banding jasper – Jasper showing a banding similar to agate, often brightly colored, and coming from many localities. See RIBBONSTONE.


B & S gauge – Standard American gauge used for measuring thickness of wire and sheet. Used more frequently by silversmith than jewelers who prefer the micrometer or douzieme gauge.


bangle – A solid or hollow non-flexible bracelet, a wire bracelet.


banking – 1. Any solid or adjusting stop for escapement to limit its movement. 2. Roller jewel striking outside of fork due to excessive motion of balance. Also called REBANKING.


banking, magnetic – In electrical watches, a permanent magnet draws and retains the indexing fork to a side.


banking, over – The result of the pallet fork’s accidental movement to the opposite banking, thus preventing the roller jewel from entering the fork and thus stopping the watch.


banking pin – Perpendicular pin acting as banking for the angular movement of the pallet.


banking screw – An eccentric screw projection allowing the pallet banking to be adjustable.


banking to drop – Adjusting the banking of an escapement so that the fork drops off a pallet jewel without further angular movement (without slide).


bar jewels – Archaic European term meaning jewels for train-pivot bearings.


bar movement – A design of watch movement in which pivot-bearings are all in bridges, so that all train wheels are visible. Also called “bridge movement.”


Bar setting – Similar to the channel setting, it is a circular band of diamonds or gemstones that holds each stone in by a long thin bar, shared between two stones.


barette – A term for the pallet cock or bridge.


Barion cut – A patented square-shaped mixed cut a for diamonds, introduced in 1971 by Basil Watermeyer of Johannesburg, South Africa; named after his wife Marion, with the first letter of her name replaced by that of his. A full emerald cut crown is combined with a brilliant cut pavilion, modified by four half-moon facets parallel to the square girdle, and with four pavilion facets that form a cross when seen through the table. It rivals the round cut for brilliance, surpasses the round cut in weight retention. A square barion cut diamond has 61 facets, excluding the culet.


barium glass – A highly refracting glass once used to imitation gems. Batium increases both the relative weight (specific gravity), and the reflecting power (brilliance).


barium titanate – A white srystalline compound used as a ceramic transducer in ultrasonic cleaning devices.


bark finish – An attractive finish produced by engraving somewhat wavy lines, roughly parallel to each other. It is most often formed with an eccentric knife-edge cutting wheel in a flexible shaft machine. Watch cases, bracelets and dials are often ornamented in this way. So called for its similarity to tree bark.


barleycorn – A kind of decorative engraving on metal, produced by a geometric lathe. See ENGINE-TURNING.


barley twist – Twisted columnar decorations on clock cases.


Baroda gems – (ba-roe’da) Term used by one ring manufacturer for glass cut like diamonds and backed with foil to increase their brilliance.


barometric error – The deviation of a timepiece due to changes in altitude or barometric pressure.


baroque – Irregular shape of gem or pearl.


baroque pearl – (ba-roke’) Pearl of irregular form


barrel – The hollow short cylindrical box in which a mainspring is housed. In a “going” barrel, the arbor turns only in winding the spring; teeth on outside of barrel turn the center pinion. In a “motor” or safety barrel, the teeth are on a separate (main) wheel and this turns with the arbor as the watch runs, the barrel remaining stationary and turning only during the winding of the spring. See FUZEE, SUSPENDED BARREL.


barrel arbor – Arbor on which the mainspring barrel turns and which turns for winding the mainspring, in going barrels; or which carries the pivots of the main wheel in motor barrels.


barrel, hanging – Barrel whose arbor is supported at one end, used in thin watches.


barrel plating – Quantity electroplating in rotating barrel. See ROTATING BARREL, TUMBLING.


barrel shape – A gem shape with flat top and bottom and rounded sides.


barrette – (bah-ret’) 1. An ornamental bar, with a pin and clasp mounted on the back, to be worn in the hair. 2. A file with teeth cut on lower side, and its back uncut and of ridged cross section, also known as a safety back file. 3. The pallet bridge.


basanite – (bazz’a-nite) A name which has been given to a black compact fine-grained quartz which is used for testing precious metals by observing the color of the streak made upon it. See TOUCHSTONE, LYDIAN STONE.


bascine – (bah-seen’) The form of joint between the center and the back or bezel of a pocket watch case in which the joint when closed is invisible, without a ridge or bead.


bascule – (bass-kule’) Describes the French form of chronometer escapement with a pivoted arbor and spiral spring to mount and operate the detent, instead of the English form with a one piece spring to perform the same functions.


bascule setting – A watch winding mechanism set into a pivoted rocking bar to shift the wheels into winding and setting phases.


base metal – Any non-precious metal.


basket-setting – A fancy setting of various shapes with numerous sides piercing that provides a basket work or lacy appearance.


basse-taille – (bahs-tie) An enameling technique whereby transparent enamels are placed over chased or engraved designs in metal and fired. The variations in thickness produce interesting gradations of color.


bastard amber – A cloudy amber. See BONY AMBER, BLUE AMBER, AMBER.


bastard file – A rough, course cut file.


bastite – (bass-tite’) A variety of greenish serpentine with a patchy sheen. It is used in small art objects. The luster comes from the coarse crystal grains of original mineral bronzite, which has been altered to the serpentine. See SCHILLER SPAR, VERDE DE CORSICA, CALIFORNIA CAT’S EYE.


batata roxa – Brazilian name for the brownish-violet colored tourmaline which is usually called rose in the trade.


baton figure, hands – Hands or figure resembling the flat, short, straight Roman sword.


battery – A unit of electrical energy composed of two or more cells; however, common usage refers to even a single energy cell as a battery. b>1. Watches. Watch batteries are composed of a top anode (-) with its insulating seals, crimped into bottom cathode (+) can. The anode material is zinc amalgamated with pure mercury or silver oxide, topped with a barrier and electrolyte. When the (-) and (+) are “loaded” by the demands of the watch, electrons flow from the (-) to the (+). Batteries designed for LED, LC-digital, analog and sonic watches are seldom interchangeable; hearing aid batteries should never be used in watches. Most watch batteries are designed to meet their normal requirements for more then a year. 2. Clocks. Clock batteries are of similar compostion, but their shapes may very depending upon the space available.


battery, rechargeable – Any form of electrical cell whose depleted energy may be restored by charging from an outside electrical source.


battery strap – The metallic bridge to secure the battery to the movement.


Bavarian quartz cat’s-eye – Quartz with actinolite inclusions that give to cabochon-cut stones the eye-like reflection streak. Formerly found near Haid and Treseburg-Bodetal in the Harz. See HAWKEYE.


bayonet case – A water-resistant case whose back is secured in a fraction of a turn in a sturdy slot-piece.


bead – 1. A narrow semi-circular moulding such as an astragal. 2. A form of stone cutting suitable for stringing, necklaces, etc. 3. A hollow metal sphere used in necklaces, etc. 4. A circular or elliptical stone worn as part of a neckchain or bracelet. 5. One of a number of fasteners raised from the background metal to secure stones. See BEAD SETTING.


bead setting – A method of diamond setting in which the stones are set flush in a strip of metal. The stones are held by the beads which are raised by the diamond setter from the surrounding metal.


beading – 1. A variety of gem-stone setting in which the clamps over the edge of the stone are formed by pressing into the metal a punch which has a hemispherical hollow, which forms the bead. 2. A detail of ornament on jewelry, watch cases, etc., consisting of a row of hemisphere beads pressed into metal.


beak – That part of a chronograph return-to-zero lever that contacts the heart cam.


bearded girdle – Tiny, hair-like cracks extending into a diamond from the girdle, caused by excessive speed in bruiting. The girdle looks fuzzy, lacks the normal smooth, waxy finish.


Bearding or girdle fringes – The outermost portion of the stone, called the girdle, can develop small cracks that resemble whiskers during the polishing process. The bearding can sometimes be removed, if not too dramatic, with slight re-polishing, and if the weight allows.


bearer – 1. Holes in the framework of a timepiece movement in which pivots run. The bearing of pivots which run at the greater speeds, in “jeweled” watches, are jeweled to reduce friction and wear. 2. The groove or shoulder in which a stone is fitted in a piece of jewelry.


beat – 1. “Out of beat” is a condition in which a balance or pendulum has uneven extant of motion on the two sides of its line of centers, which is indicated by the uneven sound of the beats. When this is corrected, the balance or pendulum is said to be “in beat”. 2. Beats per hour, or “the train” of a watch, are the number of impulses given to the balance per hour by the escapement, such as 21,600, 19,800, 81,000, 16,200, etc. This number is fixed by the total gear ratio of the train between center wheel and escape wheel, inclusive, and must be matched by the beat-number of the balance assembly.


beat tool – A tool to twist the hairspring collect to effect the “in-beat” condition.


beccarite – (bek’ka-rite) An optically abnormal olive-green zircon, found in Ceylon.


beckerite – A variety of amber without commercial value.


beef-blood ruby – Said to be a name for a color grade of ruby, of deeper red than the pigeon-blood.


beekite – An atized coral in which the white coral skeleton stands out on a flesh-red back-ground. Found near Aden and elsewhere. Erroneously called backite.


bed – The flat main part of a lathe body upon which the head and tailstock and attachments are mounted.


beeswax – Wax produced in beehives used in jewelry making as a lubricant for wire drawing, sawing and, occasionally, drilling.


beggar beads – Necklaces of hand-cut quartz stones made so inexpensively in India that even beggars can afford them. Some strands are graduated beads of one stone and shape. Other combine many shapes, sizes and colors of jasper, agate, carnelian, moss agate, bloodstone and chalcedony.


Behr loupe – A magnifying loupe in which the lenses are mounted on a hinged clamp to be attached to a spectacle-frame, so that the loupe lenses may be swung away from in front of the spectacle lens, when not being used. See LOUPE.


Beilby layer – A thin layer of vitreous amorphous material on the surface of polished stones, other then diamond, caused by melting and flowing during the polishing process; named after Sir G. T. Beilby, who expressed the theory in 1921.


Bek process – A patented method of encasing a base-metal article with continuous precious-metal coating. After being electroplated with gold, platinum, or a gold alloy, the article is subjected to a heat treatment to being about diffusion between coating and basis metal, to modify the composition, color and wearing qualities of the coating, and through annealing and precipitation hardening to control the physical properties of the base metal.


belcher setting – A type of ring mounting with the setting claws formed in the shank of the ring.


bell – A gem shaped similar to the tulip shaped, but with central peak.


bell chuck – A split, stepped concave lathe ollet used to hold a variety of disc-shaped objects such as wheels, rings, and coins. Usually, the largest diameter of this chuck well exceeds that of its main body.


bell-metal – An alloy of copper and tin, a variety of bronze, which is one of the best materials for laps for polishing staffs, pivots, etc., used with diamantine, rouge, etc.


bell pearl – Bell-shaped pearl.


bell punch – A staking punch whose end is concave, bell-mouthed, used to contract metal parts.


bell standard – The base or boss upon which the bell of a timepiece is fixed.


balomorite – A variety of moonstone found in northern Russia near the White Sea.


bench shears – heavy duty shears, fastened to a bench. Used for cutting heavy metals.


bench key – A flat, round metal disc with numerous radial prongs in the form of watch or clock keys of varying sizes.


bench vise – A small accurate vise used on a watchmakers bench.


Bangal anethyst – Misnomer for purple sapphire.


benitoite – (be-nee’to-ite) A barium titanium silicate. It is blue in color and resembles a sapphire, but is much softer (6½ in hardness) and shows, in the dichroscope, a strong color contrast, blue and white. Gem material is found only in San Benito county, California, hence the name. It is an attractive, but little used gemstone, and if more common would un-dubitably be more popular. An expert can recognize this gem by a violet color almost always to be seen in the reflection near the girdle, a result of dispersion over double that of sapphire.


bent top – A rounded top cutting of a deep stone, in which the girdle follows the curve of the top.


benzene – C6 H6, flammable, volatile coal tar solvent.


benzine – A liquid used for cleaning thickened oil and dirt from watches and clocks, a product of distillation of crude petroleum.


beryl – (bear’il). An important mineral, the ore of beryllium and one which has several gem rep-resentatives. It is a beryllium aluminum silicate, which crystallizes in six-sided prisms. The gem varieties all have special names such as emerald, aquamarine, morganite, golden beryl, heliodor, vorobievite and goshenite. See BIXBITE, AEROIDES, CHRYSOBERYLLUS, CHRYSOLITEM, CHRYSOLITHUS, HYACINTHOZONTES, AMETHYST-BASALYTINE, DAVIDSONITE, AQUAMARINE-CHRYSOLITE. It comes in many colors and shades, has a hardness of about 8 and, except emerald, is a durable stone. It is rather low in reflective power and consequence depends for its beauty upon color rather than brilliance.


beryl cat’s-eye – A variety of beryl which contains the parallel inclusions which create the cat’s eye effect in a finished cabochon gem. See CAT’S-EYE, ASTERISM.


beryl triplet – See AQUAMARINE TRIPLET.


beryllite – A trade-name applied to synthetic rose inel, colored with chromium oxide.


beryllium – (be-rill’i-um) A very hard elemental metal, used as an alloy in metals for various uses in horology and jewelry work.


beryllonite – (be-rill’o-nite). A sodium beryllium phosphate. The colorless crystals found in Maine are sometimes cut as a gem for collectors.


berylloscope – (be-rill’o-scope). A filter for viewing gems to aid in their determinations. See CHELSEA FILTER, DETECTOSCOPE, EMERALD FILTER.


bevel cut – Stones with a large table and the edges beveled by a single facet; the bottom may be cut normally, or it may be the same as the top, in which case it is known as double bevel cut.


bevel gears – Pairs of pinions with leavers at angles to transmit power at a right angle; for example, in stem-winding work in watches.


bezel – (bezz’el). 1.The upper part of a gem, the crown facets, namely those above the girdle. Also spelled bezel, and bizel. 2. A continuous groove of a form to fit a stone in a piece of jewelry, with metal at top of groove burnished over edge of stone to form a setting. 3. The grooved ring forming part of a watch case, around the dial, into which the watch crystal is fitted. 4. In silver hollowware, the projecting flange or lip inside a cover or lid fitting the latter to the body of the vessel proper.


bezel cutter – A tool to cut or mill the under-cutting in a bezel crystal.


bezel facets – Also called top main facets; four of the eight four-sided facets that alternate with the four similarly-shaped top coner or quoin facets between the table and the girdle of a brilliant cut diamond. Some cutters and many jewelers apply the term bezel facets to all eight facets. In Great Britain all eight are called kite facets; in Scandinavian Diamond Nomenclature, upper main facets. See BRILLIANT CUT.


B.H.I. – British Horological Institute.


bias – In an electrical timepiece, a steady voltage placed in series with a transistor.


bifilar – A wire with two sets of winding as used in electronic watches with both sensing and impulsing coils.


Billston show watch – Dummy porcelain-form watch used by poor to affect status of watch ownership.


bimetallic balance – A compensating balance, with laminated spilt-rim made of brass outside and steel inside. See BALANCE.


binding wire – The soft iron wire used for binding together parts of jewelry etc., while being soldered.


binnacle watch – Timepiece ringing nautical time invented by Morris Tobias of Wapping in 1812.


bipolar circuits – Containing two magnetic poles as used in electrical timepiece.


bird’s eyes – American fresh-water pearl term for slightly imperfect pearls with dark rings.


bird’s eye quartz – A colored jasper containing colorless quartz spherules.


bird wing pearl – Wing-shaped baroque (usually fresh-water) pearl.


birefringence – (bye’ree-frin”gence). A technical word for the separation by a doubly refracting crystallized substance of single rays of light which have been broken into two rays and made to vibrate in two planes at right angles to each other, moving at different speeds. The amount of separation may be great or small, but in only in a few cases, such as peridot and zircon, is it sufficiently strong to be visible to the naked eye. When pronounced, as in those gems, a doubling of the edges of the back facets, as seen through the table, is easily recognizable; if weak, it may often, on colored stones, be detected in a dichroscope, which separates the two rays and shows their color differences, or by a polariscope. See ANISOTROPIC, DOUBLE REFRACTION, INTERFERENCE COLOR.


birthstones – Stones which have been selected as appropriate and lucky for wear by people born in the respective months; mounted in rings, earrings, and other jewelry. The list, adopted by Retail Jewelers of America Inc. in 1912, follows: Jan., garnet; Feb., amethyst; Mar., aquamarine or bloodstone; Apr., diamond; May, emerald; June, pearl, moonstone or alexandrite; July, ruby; Aug., period or sardonyx; Sept., sapphire; Oct., opal; Nov., topaz or citrine; Dec., turquoise or zircon. By Federal Trade Commission rule, it is unfair trade practice to use the word “birthstone” or the name of any precious or semi-precious stone as described of a synthetic, imitation or simulated stone unless preceded by the word “synthetic”, “imitation”, “simulated” or other word of like meaning to disclose the fact that it is not a natural stone.


biseau case or movement – A bevel-edged movement or case.


bismuth – An elemental metal, much used in alloying solders to produce a solder that will melt at extraordinarily low degrees of heat.


bit – The second-bit is an enamel watch dial is the circle of enamel soldered or cemented in the main dial and forming the second-dial. The center-bit in a “double-sunk” dial is the piece cemented or soldered or soldered inside the hour-circle and forming the center of the dial.


bitellos – Brazilian term for large diamonds.


biting-in – A term used in etching to describe the action of acids on metals such as copper, silver, or steel, on those parts which are not covered with a resisting substance. See ETCHING.


bivouac watch – A special-feature watch that shows altitude and barometric pressure, used by mountaineers and parachutists.


Biwa pearl – A cultured pearl, originally non-nucleated, grown in a fresh-water mussel in the vicinity of Lake Biwa, Japan.


bixbite – Name given to small pale red crystals of beryl which are found in topaz pockets in portions of the Thomas Range, Utah. Recently more interesting because of the discovery of deeper red and larger crystals of this type in the neighboring Wha Wha Range, mostly embedded in rhyolite, and even now capable of yielding only minute stones of a rich red hue.


black-centered stone – A lumpy diamond with overly deep pavilion. When viewed face-up, the reflection of the latter in the center of the table are black. Also called dark centered.


black coral – A black coral-like substance, but distinct from precious coral. Divided again into true and false black corals depending upon the animal responsible for its formation. The luster is horny to pitchy. The hardness 2.5 to 3, and the color ranges from dark brown to deep black, but rarely is light brown to pale yellow. Comes from Hawaii, Malay Archipelago, the Red Sea, and a little in Bermuda and the Mediterranean. It is used in art objects, beads, bracelets, knife handles, etc., especially in the Orient. See ACCARBAAR.


black dermographism – (der’moe-graff-ism) Literally, “black writing on the skin;” a phenomenon sometimes reported by wearers of precious-metal jewelry. Caused by relatively hard chemicals in cosmetics, medicated creams, lotions and toothpaste- such as zinc oxide, titanium dioxide, ferric oxide, calamine and pumice- lodging on the under side of rings, bracelets, necklaces, and pins. Often with hardness 6, such particles abrade the jewelry metals (gold or silver, hardness 2), depositing a fine, black metallic powder on garment or skin. The particles look black because they are too small to reflect light. Stainless steal or chromium are too hard to abrade; high-karat gold alloys, being soft, smudge more readily than do harder, lower-karat alloys. See NICKEL DERMATITIS.


black diamond – A term used for truly black diamonds, for carbonado, and for hematite.


black onyx – Almost unknown in nature; produced in Idar-Oberstien, West Germany, and elsewhere by warming chalcedony in a sugar solution for several days or weeks; then placing the stones in warm sulphuric acid, which reacts with the sugar, precipating free carbon. The color is permanent; no tests exist to determine the artificiality.


black opal – A precious opal of a dark hue, blue, gray, or black (red to grey-brown in transmitted light), in which the color play stands out. See PRECIOUS OPAL, OPAL.


black pearl – Natural Oriental pearls from grey to almost black.


black-treated opal – A granular type of whitish Australian opal, black treated by a variation of the sugar method used to transform chalcedony into black onyx. Such stones are almost opaque and do not fluoresce under ultra-violet; with magnification, carbon can be seen along the fissures. Certain Mexican opals, blacked by smoke and heat, have a dark brown to black body color with vivid color flashes.


Black Velvet – Trade name for an electrochemically produce deep black finish on gold jewelry.


bleaching – 1. Pearls. The routine treatment of pearls and cultured pearls with peroxide when first finished, at which time they may be tinted pink, blue, or black. 2. Gemstones. Some brown tiger-eye is bleached light brown, and then perhaps recolored in an unnatural hue. Turquoise, dulled by skin-oils, has been bleached to its former attractive hue. 3. Ivory. Ivory is sometimes bleached to remove oils absorbing in handling.


Blemishes – The term blemish is used when the diamond has scratches or marks on the external area of the stone.


blister pearl – A one-sided pearl attached to the shell, not a true free pearl.


bloc – Large cleavage fragment of diamond.


blocking – The initial shaping of a brilliant, putting on the first 17 or 18 facets which are later divided in brillianteening.


blood coral – Name applied to precious red coral.


blood drops – Water worn red spinel pebbles.


blood enamel – An ancient imitation coral.


blood jasper – Heliotrope or bloodstone.


bloodstone – Same as heliotrope, formerly known as hematite.


blow pipe – A small mouth-pipe for blowing a blast-flame for hardening steel, soldering, ect.


blower – A mechanical generator of compressed air, either of bellows or rotary pump type, for supplying a blast-flame for heat-treating and soldering metals is horology or jewelry work. See COMPRESSOR.


blue amber – Trade-name for light-colored, highly valued bastard amber, with something of the bluish color of diluted milk.


blue chalcedony – Chalcedony which is naturally, or artificially, blue in color. The naturally blue is somewhat dull and grey, fairly well-colored pieces are known in the Siebendũrgen and the Mojave Desert. Probably most blue chalcedony is dyed. It is wrongly called sapphire, and there is danger of confusing it with the rare gem mineral of the same name. See BLUE MOONSTONE.


blue chrysoprase – Chrysocolla-stain chalcedony


blue earth – The name given to the gray-green sand bed in East Prussia near the shores of the Baltic in which amber occurs. The bed is between 12 and 18 feet thick and is mined at Palmnicken, where it lies about 140 feet below surface. It only outcrops below sea level and storm waves wash out the light amber and cast it on the shore.


blue gold – An alloy of light blue color usually composed of iron and gold.


blue ground – The fresh rock of the diamond pipes, in which the diamonds occur. See KIMBERLITE.


blue jasper – A dyed fine-grained quartz rock sold under the name of Swiss lapis.


blue John – A banded variety of fluorite, used in carved art objects, coming from Derbyshire, England.


blue moonstone – Name given to blue chalcedony.


blue onyx – Dyed chalcedony. See ONYX.


blue pearl – 1. Naturally bluish-tinted pearl, usually cultured, which is discolored by mud inclusions under the nacre. 2. The dark-hued Pinna pearl, from La Paz and Panama.


blue-remover – Acid used for whitening steel after color-tempering. Hydrochloric acid, or a mixture of equal parts of sulphuric and hydrochloric acids, is mostly used.


blue spar – Lazulite.


blue Wesselton – An early color grade for diamonds, between River and Wesselton; sometimes called Top Wesselton.


blue white – Term to describe the color of a diamond. It includes anything from a Jager to a Silver Cape, since bluish glints in dispersed light tend to counterbalance the body color of all grades except Capes and Yellows. By Federal Trade Commission rule, it is an unfair trade pratice to use the term blue white, or any other term, expression, or representation of similar import as desciptive of any diamond which under normal, north daylight or its equivalent, shows any color or any trace of any color other than blue or bluish. Better Business Bureaus recommend avoidance of the term, and the American Gem Society prohibits its use.


bluestone – A name sometimes given to Water-of-Ayr stone, used as a lap for flattening brass, gold, etc., made into watch or clock parts, prior to polishing or other finishing operations. This term should not be confused with bluestone meaning sulphate of copper or blue vitriol.


bluing – One of the colors resulting from slowly heating hardened steel. The colors form yellow, brown, purple, and finally blue. Besides bluing steel for tempering its working qualities, it is also done to obtain a pleasing color on watch parts, screws, springs, hands, etc.


bluing pan – A shallow flat pan in which polished steel parts are placed for bluing by heat.


blunt hexagonal barrel brilliant – A type of stone cutting employed for beads.


blunt hexagonal barrel faceted – A type of stone cutting employed for beads.


boakite – Local Nevada name for a naturally shattered and recommended green and red jasper.


bobbing – Sand bobbing is a process used for polishing soft metals and removing scratches, pit marks and other imperfections without dragging the metal.


bobbing compound – A tripoli type compound used as a fine abrasive before polishing.


Bobrowka garnet – (Bob-row’ka) Demantoid garnet, from the name of a brook in the Urals along which they were found in gold panning operations.


bocco de fogo – Brazillian name for tourmaline with a pink center and a green margin, commonly known as watermelon tourline.


Bohemian chrysolite – Moldavite.


Bohemian garnet – Dark red pyrope garnet.


boiling-out-pan – Copper or ceramic-lined pan to boil acid in finishing parts or dissolving broken-off screws in watch plates.


boke – Japanese name for pale rose-colored coral.


Boley gauge – A Vernier slide gauge of light construction convenient for use by watchmakers and jewelers.


Bombay – v.t. Trade vernacular meaning: To cut a stone for maximum diameter, regardless of ideal proportions; derived from Asian practice of “spreading.”


Bombay pearl – Arabian or Red Sea pearl, commonly marketed through Bombay.


bombé – The convex surface related to watch jewels or dials.


bonamite – (boe’na-mite) Misleading trade name once applied by one firm to the blue-green smithsonite from Magdalena, N.M.


bone turquoise – A substitute for turquoise, composed of bone, teeth or ivory, naturally, or artificilay tinted blue. See ODONTOLITE.


bony amber – A variety of opaque amber resembling ivory or bone, white to brown in color, and somewhat softer than other ambers. See BASTARD AMBER, SEMI-BASTARD AMBER.


boot – Term used to define the boot-shaped part of the watch regulator in which the hairspring’s active length can be adjusted.


boracic acid – (Or boric acid). An acid in crystal form used as an anti-oxidizer. See ANTI-OXIDIZER.


borax – 1. A chemical substance used as a flux in soldering precious and other metals. Borax of lump form rubbed with water on a slate, or as crystals powdered and dissolved in water, is applied to the joint and the pieces of solder thereon, before heat is applied to melt the solder. 2. A slang term used to denote unethical merchandising practices, such as selling inferior goods at inflated prices, and making exaggerated claims and statements in advertising or selling.


boring chuck – A drill chuck.


Bornholm diamonds – Misnomer for quartz crystals from marl concretions at Laesaa and Olanaa, Denmark.


borosilicate glass – (boe”roe-sill’i-kate) A sodium, boron, silica glass used in imitation gems. The refractive index is ca. 1.50, the gravity 2.36.


bort – An old French word meaning bastard and applied variably to low quality diamonds, either the poorest quality, usable only for cutting purposes (Africa) or to all diamonds of non-gem quality. Also spelled boart, boort, bortz, and bowr. See BALLAS, CAPBONADO, BLACK DIAMOND.


boss – 1. A protuberant ornament. 2. A swage or die for shaping metals. 3. Raised part of a watch bridge such as for a crown wheel bearing or upon which the regulator racquet is seated.


Boston caliber – Term used by the Swiss to define their imitations of the 18-size American watch movement and upon which they placed names of American communities. Later outlawed by U.S.


bottle stone – Moldavite.


bottom corner facets – The large four-sided facets which alternate with the pavilion facets on the pavilion of a brilliant. See PAVILION FACTS.


bottom plate – Main plate of a watch movement.


boulder opal – Brown iron oxide nodules containing opal-filled fissures, found in the opal beds of Queensland, Australia.


boule – French term to describe the fused mass from a Vermeuil furnace. The earliest products were ball-shaped, whence the name, but now they are greatly elongated and even the German term birne (pear) is inappropriate.


Bourguignon pearls – (boor-gee-nyawn’) Earliest imitation pearls of wax-filled glass beads coated with a “pearl essence” made from fish scales.


Bourse – diamond-trading markets where members buy and sell good.


bow – 1.The ring or hoop on pendent of a watch case, to fasten swivel of watch chain to. 2. A curved length of metal or whalebone, with cord stretched between its ends, for use in driving pulley in a bow-lathe.


bow lathe – Small lathe using a bow and string to turn the work to be cut.


Bow-tie Effect – area of less brilliance that appears like a bowtie; occurs in certain fancy-shape diamonds when the stone’s proportions are poor.


bow-opening pliers – Long nosed pliers whose ends open when lower arms are squeezed, to spread open watch pendant bows.


bowenite – A variety of serpentine resembling nephrite and often confused with it. It is called tangiwai by the New Zealand Natives and sang-i-yeshen by the Chinese.


bowr – See BORT.


box, annealing – A closed receptacle for annealing steel, packed with sand or metal filing to exclude oxidization during heating.


box chuck – Lathe collet with large hollow cylindrical extension in which are a large number of setscrews to hold object to be turned eccentrically.


box compass – Compass housed as a marine chronometer. See BOX CHRONOMETER.


box setting – A setting for a stone in a ring, the top edges of the “box” being burnished over edges of stones to hold stone setting.


boxwood – Fine-grained hard wood, from the slow-growing true boxwood bush – used for laps for polishing steel because it has so close a grain and is free from gritty matter. Its sawdust was for dying watch parts and jewelry, after cleaning.


brace – The extension of a mainspring in a self-winding watch, designed to provide traction against the barrel wall, but to slip when almost fully wound.


bracelet – A circular ornament for the arm, of ancient origin; frequently set with jewels. Bracelets of gold, dating earlier them 3000 B.C., have been recovered from Egyptian tombs.


bracelet watch – A watch worn on a band or bracelet on the arm – particularly a wristwatch.


bracelet clock – Usually a clock requiring a bracket but with a carrying handle on top. Most often today without the bracket.


brake lever plate – Lever or plate in which used to stop the balance.


bras en l’air – An old sector watches with human figure whose arms are raised to indicate correct time when the pendant is depressed.


brass – An alloy metal composed of various proportions of copper and zinc-an average formula is 65 parts copper and 35 parts zinc.


braze – To solder or weld with brass; a form of hard soldering.


Brazilian chysolite – Chrysoberyl. See CHRYSOLITE.


Brazilian diamond – Often a misnomer for rock crystal quartz. Many true diamonds are found in Brazil, so it is very confusing misuse.


Brazilian emerald – Misnomer for green tourmanline, abundant in Brazil. Especially bad since true emeralds are known from Brazil. See BAHIA EMERALD.


Brazilian pebble – Quartz.


Brazilian peridot – Misnomer for light-colored green tourmaline. See TODO MUNDO


Brazilian ruby – Misnomer for a red or pink topaz, developed by heat treatment of a normal brown stone.


Brazilian sapphire – Misnomer for blue tourmaline, or, more rarely, light blue to white topaz.


brazilianite – A hydrous sodium aluminum phosphate occurring in a pegmatite in Minas Gerias, Brazil, in large yellow green monoclinic crystals and subsequently discovered in New England dikes. It has been cut into clear yellow greenish gems, with a refractive index of about 1.60; H.5½: S.G. 3.03. Recognized as a new mineral and named in 1944 by Dr. Frederick H. Pough.


brazing – Uniting metal parts by heating them red-hot and using brass solder – also called hard soldering.


break-arch – Arch above clock cases interrupted in center by a cut or a continuation in scroll work on each side.


break facets – See GIRDLE FACETS.


breast pin – A pin or brooch worn at the V of a dress.


breccia – (brech’i-a) Geoliogical term for a naturally re-cemented rock composed of angular fragments. Many decorative stones show this structure.


Breguet compensation – Bimetallic extension to the regulator acting on the hairspring.


Breguet hairspring – A hairspring whose outermost coil is raised and curved inward to effect isochronisms.


Brequet hands – Moon or crescent hands.


Brequet key – Winding key with a slanted ratchet clutch to prevent winding except in one direction.


Breguet stopwatch – Two small toothed wheels on the mainspring barrel, one of which has a blank tooth to limit the winding and unwinding of that spring.


Briacon diamond – Misnomer for quartz.


bridge – A part of the framework of a watch movement, fastened to its base by a screw at each end of the bridge, and containing one or more pivot bearing. See COCK.


bright cut – 1. An incised decoration on a surface, e.g., a spoon handle. 2. The final smooth cutting of the metal surrounding a bead set stone.


bright dip – An acid solution in which copper or copper alloy articles are immersed to achieve a bright finish.


bright finish – The finish that imparts to silver or gold wares a highly polished mirror-like surface.


bright plating – A process in electroplating whereby the composition of the solution is such that it deposits plating that has a polished appearance, requiring no buffing.


Brighton diamond – Misnomer for quartz.


Brighton emerald – Misnomer for green bottle glass.


Brillante – Trade name for synthetic, rutile structured titania.


Brilliance – When used in reference to a gem, it refers to the brightness of the stone, which is related to the surface polish and the internal reflection of light from the back facets. The ability of a stone to take a polish and the amount the penetrating light bent (the index of refraction) and eventually reflected out of the front again, from correctly placed facets, and the transparency, determine the brilliance of stone.


Brilliant Cut – A type of cutting, used especially on diamond with 58 facets, and also, now, used as a synonym for a brilliant-cut diamond. There are 32 facets, plus the table, above the girdle, and 24, plus the culet, below. See STAR FACETS, BEZEL, TOP CORNER FACETS, TOP MAIN FACETS, TOP HALF FACETS, BREAK FACETS, PAVILION FACETS, QUOIN FACETS, SKEW FACETS, SKILL FACETS, AMERICAN CUT, EUROPEAN CUT; SCAN D.N. STANDARD CUT.


Brillianteering – The process of putting the final 41 facets on a brilliant cut diamond, following blocking. See BLOCKING.


Brillonette – (bree-yon-ett’) See HALF-BRILLIANT.


Brinell hardness – An index number expressing a specific degree of hardness of a substance, found by testing with an instrument that measures the depth of penetration of the substance by a hard steel ball or point.


briolette – (bree-o-lett’) Pear-shaped stone, bounded by crossing bands of small triangular facets, used as a pendant.


Bristol diamond – Misnomer for quartz rock crystal.


brittleness – That property of a substance that causes it to break readily. Tool steel, when hardened, is extremely brittle. It must be softened or tempered to the degree of hardness required for its use. Precious metals, when contaminated with foreign substances or when improperly refined, are usually too brittle to be worked without breaking.


broach – 1. A tool used for enlarging or finishing holes. A cutting broach has faces on it lengthwise, forming cutting edges – from two to eight of them. It is slightly tapered. A polishing broach has no cutting edges but the round surface is slightly scored lengthwise, like the surface of a burnishing file. See REAMER. 2. Jewelry. See BROOCH.


bronze – 1. A reddish-brown alloy of copper and tin. 2. An artistic production in bronze, as a statue or statuette. 3. Brazilian term for greenish diamonds in which the color is in a thin outer skin.


bronzite – A variety of pyroxene with a bony hiller color, sometimes used as a decorative stone. See BASTITE.


brooch (broach or brooch) – A piece of jewelry to be worn pinned to clothing, as at the beck or shoulder, or the breast or hat, or in the hair.


brooch watch – Watch that can be worn as a brooch.


brookite – A dark-colored form of titanium oxide rarely cut as a gem for collectors.


brown hyacinth – Misnomer for vesuvianite.


brush, brass, glass – Brushes whose bristles are made of glass or brass fibers used as an abrasive.


bruting – See GIRDLING.


bubble – 1. Gemstones. An apparent void; often they are included crystals of some foreign substance, but so colorless and so different in refractive index that they resemble cavities. 2. Glass. Bubbles occur in the blowing of glass; are one of the best signs that a glass in handmade; a bubble does not weaken glass.


buckle – The crimping of metal under stress.


buff – 1. A tool for polishing watch parts after cleaning, a hand-buff of chamois leather or felt glued to a wooden handle and charged with powdered rouge. 2. A compact piece of felt or quilted cloth or leather, used with abrasive materials. Buffs are both of circular form for use in lathes, and of flat form with handle for use by hand.


buff top – A low cabochon type of cutting, the top just slightly rounded, with a faceted pavilion.


bulb opal – The variety manilite.


bullet cut – Pentagon-shaped gem-stone like a baguette except that one end is pointed.


bull’s eye – Dark-colored labradorite.


bullion – (bull’yon) Gold or silver bar, ingot or other form, as distinguished from coin.


bunch rings – Diamonds rings produced in quantity to sell at popular prices with small center stones. They were formerly sold in bunches held together with string – hence the name.


Bunsen flame – A blue, smokeless flame from a Bunsen burner, which mixes gas and air, used for various heating purpose in horology, and jewelry work. Named for the inventor, a Heidelberg, Germany, chemistry professor, R. W. Bunsen, 1811-1899.


burin – (beu’rin) An instrument of tempered steel, used for engraving on metal. It is prismatic in form, having one end attached to a wooden handle and the other end ground off obliquely, so as to produce a sharp point.


Burma ruby – Name given to the best quality rubies, most of which comes from Burma.


burmite – Amber from Burma, essentially identical with Prussian amber. Found in dark brown, dirty brown, or rarely red and light yellow water-worn masses up to skull sizes. It is mostly sold in the Orient, though much “Chinese amber” is pressed German amber or bakelite. See CHINESE AMBER.


burnishing – 1. To produce a polished surface on metal by rubbing it with a hard, smooth, highly polished steel burnishing tool or agate; this does not remove any of the metals. Object of burnishing are to brighten, harden and preserve the metal. 2. To press or swage a metal corner over the edge of a stone, etc., to hold it in a setting.


burnisher – 1. A tool for polishing metal by burnishing. In watch-work, burnishers are flat slips of smooth-surfaced hard steel, used for polishing pivots, etc. Burnishing files have one side smooth-surfaced, for polishing jewel-setting tops, filed pins, etc. 2. A tool for pressing or swaging metal over the edge of a stone, etc., to hold it in a setting.


burnout furnace – A gas or electrically powered furnace used to eliminate, by burning out, the wax from investment molds.


burnt – 1. When applied to a stone it means that the color has been changed by heating. Amethyst is so changed to citrine, brown zircons aquamarine, and muddy pink beryl often changes to fine pink morganite. Many stones are so treated. 2. Steel which has been overheated (hotter then “cherry red”) in hardening it. Burnt steel has a course grain, is brittle, and will not take a fine polish.


burr – 1. On a pivot, a “head” formed on the end of a balance pivot by a violent thrust against a cap jewel, due to a fall or blow suffered by the watch. 2. A milling cutter for forming a seat for a stone in setting a piece of jewelry, for removal of metal in hard-to-reach areas and cutting special stones.


bushing – Repairing a worn pivot hole in a metal bearing; essentially, lining the hole, after enlarging it for the purpose, with new metal in which a hole is drilled to fit the pivot correctly.


butt joint – A joint made by bringing two metal ends together and soldering or welding them on the flat without fold or overlap.


butt welding – Welding ends of metal, as in the ends of a ring shank. Forms a solder less joint. See BUTT JOINT.


butterfly jewelry – Inexpensive jewelry made from a fragment of a butterfly wing, usually blue Brazilian Morpho butterfly, covered with glass.


butting – A fault in the action of gearing in a train, in which the two wheels are too far apart or the teeth poorly formed, so that the transmission of power takes place too near the points of the teeth.


button onyx – Or button opal, is the name given to an opal-agate from New Mexico in which the common opal alternates in bands with a black chalcedony.


button pearl – A pearl which is flattened on one side.


Buxton diamond – Misnomer for quartz, rock crystal.


byon – Burnese name for the alluvial gravels in which rubies occur.


bywater, byewater – An early color-grading term applied to diamonds tinged with yellow. Same as bye.